Officers from the PSNI's serious crime branch worked in conjunction with Kent and Essex Police to make the arrest.

Mr O'Hare, 33, and his girlfriend Ms McClatchey, 21, died when they were attacked at their home at Tassagh, near Newtownhamilton. The couple were beaten with hammers before being doused in petrol and set alight.

Three brothers are currently in custody facing charges connected to the killings.

In January Martin and Niall Smith, aged 40 and 37, appeared in court, charged after being extradited to Northern Ireland from the Republic. Later the same month, Stephen Smith, 30, who was extradited from Australia, also appeared in court charged with arson.